The present invention relates to a transmitter for an apparatus that tracks the motion of a moving object in which a signal transmitting installation emits signals that are picked up by receiving equipment which then evaluates the signals to determine at least the position of the object. The position determination can be made based on coded signals in which the codes that are received do not overlap.
An apparatus of this type can be used, for example, to track the motion of a mechanical miner that is used for underground mining in applications such as coal mining. An important prerequisite for automating the excavation work is to continuously find, with sufficient accuracy, the location of the mechanical miner, such as an auger or planer, in the stope (coal face). It is also desirable to determine the velocity of motion and direction of motion of the mechanical miner.
West German Patent Application No. 2,742,367 describes a device in which a specific location is determined by means of a position pulse transmitter and a pulse counter mounted on the gearing of the drawgear of a mechanical miner.
An object of published West German Patent Application No. 3,511,504 is to determine the location of the mechanical miner in the coal face with the help of a high-frequency transmitter that is mounted on the mechanical miner which releases switching contacts when it passes high frequency receivers at stope positions along the route.
A similar device that uses polarized electromagnetic radiation in the range of microwaves follows from the published West German Patent Application No. 3,337,742. Both the transmitter and receiver are mounted at a specific stope support. Rotating the plane of oscillation between transmitting and receiving positions using an appropriate wave guide that is mounted on the mechanical miner results in a position finding function that is not easily controlled because of sweep radiation.
Another device that determines the position of the cutting head of an advance working machine or a mechanical miner is known from European Patent Application 0,105,867. This patent application discloses a heat image camera that detects the infrared radiation emitted by the heated cutting head.
Position finding devices for mechanical miners that use infrared radiation are known from, for example, published West German Patent Application 30,44,108, corresponding to U.S. Pat. No. 4,330,154, which is assigned to Dowty Mining Equipment Ltd., and further from the brochure "Dowty Mining Electronic Control, Machine Initiation by the Infra-Red System" of the same corporation. The mechanical miner disclosed in the brochure contains an infrared transmitter. The Patent discloses an ultrasonic system but states that other types of transmitters could be used such as an infrared transmitter. The receivers assigned to a given transmitter are configured at the stope supports. The West German Patent Application states that the transmitting/receiving equipment especially prevents the advancing mechanical miner from colliding with the stope supports. The distance between the stope supports and the mechanical miner is continuously measured. A locking device releases a stop signal if the mechanical miner approaches a stope support. This situation could occur if, for example, the stope support is unintentionally placed too far forward due to a control error.
Systems that use infrared radiation to position conveyor vehicles, such as coking machines, bridge cranes or traveling cranes, are also known from European Patent Application 0,150,289, corresponding to U.S. Pat. No. 4,557,805, as well as from the essay "Heavy-Duty Positioning Equipment" (Positionieranlage im rauhen Betrieb) by F. Bruns, special edition from "Electro-technik", Vogel publishing house, Wurzburg, issue 9/10, pages 1 to 4.
The foregoing position finding devices, however, have not yet been optimally designed, especially for tracking the motion of mechanical miners.